Re: [PATCH] tracing: Use task_nice() in function __update_max_tr()to get the nice value of task.

From: Steven Rostedt
Date: Wed Jan 22 2014 - 22:57:11 EST


On Wed, 22 Jan 2014 17:41:45 -0500
Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx> wrote:

> There is already a function named task_nice in sched.h to get the nice value
> of task_struct. We can use it in __update_max_tr() rather than calculate it
> manually.
>
> Signed-off-by: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx>
> ---
> kernel/trace/trace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 9d20cd9..ec149b4 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -970,7 +970,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
> else
> max_data->uid = task_uid(tsk);
>
> - max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
> + max_data->nice = task_nice(tsk);

Except that's a function call in a critical path. Switch it to
TASK_NICE(), and I'll take the patch.

Thanks,

-- Steve

> max_data->policy = tsk->policy;
> max_data->rt_priority = tsk->rt_priority;
>

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